New insights into X-linked adrenal hypoplasia congenita from a novel splice-site variant of NR0B1 and adrenal CT images

Abstract

Background: X-linked adrenal hypoplasia congenita (AHC) is a rare disorder, often manifesting as primary adrenal insufficiency (PAI) and hypogonadotropic hypogonadism (HH), and caused by variants of NR0B1, most of which are frame-shifting variants, and few splice-site variants.

Methods and results: Here, a novel splice-site variant of NR0B1 (NM_000475.4), c.1169-2A>T (patient 1), and a stop-loss variant of NR0B1 c.1411T>C (patient 2) are described in this study. We perform minigene assays for the splice-site variant (c.1169-2A>T) and determine that the variant causes exon 2 skipping. Moreover, the defect of NR0B1 protein may bring about the severe phenotype of the patient. Through 8 years of follow-up, we compare the CT images from 8 years ago with the latest image, and observe the CT image change of adrenal in patient 2 (from the increased thickness of adrenal to adrenal atrophy).

Conclusion: X-linked adrenal hypoplasia congenita is produced by variants of NR0B1. We report a case that presents a novel splice-site variant, which has been verified that it could lead to the exon 2 skipping in the RNA splicing progress. Moreover, we report the adrenal CT image change of patient 2, which has never been referred to before, and expand the spectrum of X-linked AHC characteristics.

Keywords: CT image change of adrenal; NR0B1 (nuclear receptor subfamily 0 group B member 1); X-linked AHC; infertility issue; minigene; splice-site variant.